14S 
THE YOUNG SCIENTIST. 
THE 
YOUNG SCIENTIST. 
PUBLISHED MONTHLY. 
Terms— Fifty Cents per year. J8Se" Postage free to 
all parts of the United States and Canada, except New 
York City . Our absurd postal laws make the charge for 
delivering our journal to subscribers in New York city 
five times as great as that required for transporting it 
across the continent, and delivering it to subscribers 
in San Francisco or New Orleans. We are therefore 
compelled to charge our New York subscribers 12 cents 
extra. 
The Young Scientist has been received with so much 
favor that its circulation is already greater than that of 
any other monthly Scientific or Mechanical journal pub- 
lished in the city of New York, with the exception of the 
Pojpulwr Science Monthly. It goes into the best fam- 
ilies, and has their confidence. No olap-tbap adver- 
tisements, OB ADVEBTISEMENTS OE PATENT MEDICINES 
RECEIVED AT ANY PBICE. 
Advebtising Rates— 30 cents per line, nonpariel 
measure. 
All COMMITNIOATIONS should be addressed to 
THE YOUNG SCIENTIST, 
P. O. Box 4875. 176 Broadway, New York. 
aS" For Club Bates, etc., see Pbospeotus. 
Our Trial Trip. 
TN offering four numbers as a trial trip 
for 15 cents, our object is to give to 
those who are interested an opportunity to 
examine the journal more fully than can be 
done by the inspection of a single number. 
Our rule is to send the four numbers at 
once, and the numbers that are sent vary 
from month to month, being always the last 
four that have been issued. As we keep no 
book accounts of these small transactions, 
those who remit the remainder of the yearly 
subscription are requested to state what 
numbers have been previously sent. 
A Liberal Offer. 
A S an acknowledgment of past liberality 
on their part, and an incentive to 
future efforts on our behalf, we shall give 
his own copy for 1879 free to every sub- 
scriber who is now on our books and who 
will send us the names of two new sub- 
scribers and $1.00. That is to say, we will, 
to each of our present subscribers, give 
three copies for one dollar. 
Please Renew. 
nn HE next issue of the Young Scientist 
^ is the last for this year. With it we 
complete the volume for 1878, and on look- 
ing over the matter which we have given 
and which will appear in the next issue, we 
feel that we have kept all the promises 
which we made to our young friends. Next 
year, however, we hope to greatly improve 
the journal. Each number will contain not 
less than sixteen pages of reading matter, 
and we have been enabled to add very con- 
siderably to our list of contributors. 
The December number will contain a 
title page and a very full index, so that the 
volume will be in good shape for binding. 
We have made arrangements to bind them 
neatly and cheaply. For 35 cents we will 
bind the volumes in cloth with neat gilt 
title stamped on the back. The postage on 
the volume will be ten cents, which must 
be added when sent by mail. 
As this is our busy season, we would asfc 
our subscribers to renew promptly. As it 
does not pay to incur expense in collecting 
such small sums we shall conclude that 
those who do not remit do not want the 
journal, and their names will be struck from 
our list. 
Sympathetic or Secret Ink. 
Aside from any practical purposes to which 
they may be put, sympathetic inks form some 
very interesting and curious experiments,; 
Thus, if we write on paper with a cheap solu- 
tion of acetate of lead (sugar of lead), and 
then either dip the paper in a solution of 
sulphuret of ammonia, or sponge it with that 
liquid, the letters will appear of a dark brown.^ 
To those who see this for the first time, the 
eff'ect is very curious. Unfortunately, how-^ 
ever, all salts of lead become black when ex» 
posed for some time to the air, and therefore 
they cannot be used for secret correspondence.' 
Salts of iron, prussiate of potash, and several 
other salts which would make excellent secret 
inks, are also colored by exposure to the air, 
and cannot be used. Indeed none of the sym- 
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